apple Lisa2. Any advice on non-working floppy drives?

Indeed. What non-trchnical people don't realise is that there isn't (normally) a magic box you can plug into a non-working whatever that will tell you what is wrong. Instead there are many instruments which will let you discover (in part) what the deicce is doing, but you need a brain/experience to interpret the results. II would have lookedas ther drives themselves (given that the drive was not manyufactered by Apple, and that the internal design could well have been modified druign the prodsuction run, so documentation my not be that accurate). Basically there are only 2 types of sensors used -- mechanical swtiches and LED/phototransistor light barriers. The latter may be a single component, such as a slotted optoswitch. A mechanical switch could detect the disk holder coming down, or the disk itelf in the holder (often the latter). A light barrier could be interrupted by the disk itself (rare), a tab on the disk holder, or a 'flag' moved when the disk slots into position. If it were my drive, I would take off any removeable covers and then look for swiches and sensors and see what happens when a disk is loaded and ejected manually. As an aside, one book I have on teleprinters (actually on amateru RTTY using Creed 7s, etc) suggests turnign the motor by hand (power off, of course) and operating keys, the receive magent, etc and watching just how things work. I did this and learnt a lot... (One thing, nothing to do with Apples or disk drives is that in some machines there are clutches that depedn o nthe motor speed to latch up properly., If you turn the machine slowly by hand, you need to latch them up manually before applying power (or at least release them as soon as possible after applying power to the motor so they can latch up properly. Otherwise they will wear very quickyl). Actually, I have learnt many times over the years that the thing which is so obvious that it's not checked is the cause of the problem. Been cuaght by things like that more times than I can remember. I know that the Sony full-height 3.5" drives used in soem HP machiens certainyly have a disk-inserted sensor that lines up with the HD hole and such drives will not detect HD disks. I've heard 2 explanations of this : It prevents you using HD disks in drives without sufficient write current to write them properly ; or having put a sensor in that position it made sense to keep it there and use it for the HD detection. I don't know. I think i'd been assuming that as the Lisa has a very non-standard disk format (I assume it's GCR), that you would have been using real Lisa disks in that nothign else could he read by the machine. And that would have implied DD. I didn't ealise you were using a scratch disk just to see if it tried to read it. I see from your other message that this seems to have been at least part of the problem. WIthout a Lisa disk, I guess you can't be sure it's working properelt, but at least it detects and spins up the disk now. -tony